IF reforming Atomic Kitten has made Natasha Hamilton’s professional life whole again, to echo one of the girl group’s biggest hits, starring in the 20th anniversary production of musical Rent has made her appreciate it all the more.

The Tony Award-winning Broadway show follows a year in the life of a group of friends struggling to make it in New York. And the singer and actress remembers the uncertainty of not knowing whether or not she and her band mates, Kerry Katona and Liz McClarnon, would make it.

While record books tell you their debut single in late 1999 made the top 10 and that they were on their way to becoming one of the UK’s most internationally successful girl groups with more than 10million worldwide record sales, their peak is ancient history in pop terms and Natasha left the group in 2004.

Since reforming for ITV2 show The Big Reunion, however, they are starting out all over again and she is making the most of all the opportunities that come her way.

The 30-year-old said: “I’m over the moon. I haven’t stopped this year since the whole Big Reunion show. We’ve got back together as a band and now I’m going to be appearing in Rent.

“I can relate to what the characters in the show are going through 100 per cent. I have been in that position before, wondering if I’m going to make it. When I am on stage I will be able to channel those feelings because I know exactly where they are coming from.

“What’s different this time in Atomic Kitten is we are in charge. We are not little girls who can be pushed from pillar to post.

“We’ve been there – we know we have to look after ourselves because if we are not in tip-top condition, we are not going to be able to do a good job. But also we know this is our second chance. Not a lot of people get that opportunity.

“So we are loving it – we want to work as much as we can. It has made me more ambitious. We are definitely putting in the time and working hard, and it is starting to pay off already.”

With Atomic Kitten’s second coming taking off, Rent came out of the blue. The show, which is loosely based on Puccini’s La Boheme, is set in the East Village of New York City, and follows a group of struggling artists as they find themselves and their voice, living under the shadow of HIV/Aids.

Natasha, who first appeared on stage in the lead role of Mrs Johnstone in the West End show Blood Brothers, is playing the part of Maureen, a lesbian performance artist, a role that she knows will push her.

She said: “For me, acting on stage is a totally different feeling from singing. When I am singing, nothing else matters. I just let go and I am there.

“When it came to acting, I felt nerves for the first time in years. I have been singing my whole life, but I am not a trained actress, although it is something I have always really wanted to do.

“So I am a lot more nervous, but those nerves really stoke the fire in your belly and make you want to succeed even more. It’s a totally different feeling. There’s a little bit of fear there, absolutely, but I like the challenge.

“It’s the 20th anniversary of the show this year. They’ve already toured once and it’s come back by public demand. I was approached and said yes straight away.

“Blood Brothers was my acting debut and I loved every minute of it. I loved getting involved in that character – the whole experience gave me a passion for my career again.

“To play the role of Maureen is a totally different role from Mrs Johnstone. She has a boyfriend, she cheats on him, she has a girlfriend, she’s a little bit heartless, she just does what she wants to do, really.

“She is definitely a free character and I am looking forward to just being able to let my inner flirty self out on stage. I can really have fun with this character, and she sings some amazing songs, so I am looking forward to getting out there and doing it.

“I have never played anything like her before. When I was told it was the part of Maureen, I laughed out loud. I just thought, ‘Yeah, why not? I’ll give it a go.’”

On top of Rent and the return of Atomic Kitten, she is, of course, a mother. Natasha has three sons, Josh, 10, Harry, eight, and Alfie, three, none of whom seem particularly impressed by all her achievements.

She said: “The kids are so blasé about it, which I am grateful for, to be honest. They are used to seeing Mummy go off to be on stage or play gigs.

“When the whole Big Reunion started I was saying, ‘Are you excited to be coming to see Mummy performing in London?’ And they were like, ‘To be honest, Mum, Atomic Kitten’s not really our thing, we’re into Tinie Tempah’.

“But they came to the Hammersmith Apollo gig and when they came back to see me afterwards they gave me a big hug.

“I asked them, ‘Thumbs up or thumbs down?’ And they gave me a big thumbs up and said, ‘Mum, you were good’. They are fans really.”

The reaction to The Big Reunion, which lifted the lid on the highs and lows of six chart-topping groups – including Five, B*Witched, Liberty X, 911, Honeyz and Blue – took everyone by surprise, not least Natasha, who originally left the band in 2004 because she was suffering from post-natal depression.

She said: “Initially, when the idea was pitched to us, my first instinct was, ‘Yes, I definitely want to be a part of that. It’s a great idea.’

“Enough time had passed for me to want to revisit it. I just wanted to put the bad times behind me and just move forward and have fun with Atomic Kitten.

“To be honest, all the stuff we’d argue about was really petty, silly stuff. I am really loving my relationship with the girls – they are like sisters.

“We are there for each other and we are not going to get into the silly arguments we used to.

“We are doing this for our families and our kids so it’s rewarding. We get to go to work doing a job we love and we get to provide for the family as well. We see it in a different way now and we are a lot more relaxed about it.”

She added: “We are in the studio writing music, we have already recorded a new single and there are lots in the pipeline – we have gigs throughout the summer.

“It’s a nice feeling because for me, being on stage is where I feel I belong. Whether it’s acting or singing, it’s what I have always done and I feel I am me when I am doing that.”